WOW! I'll add another "I think..."

OK, in my experience, if the game uses up all of it's animations, it will start taking away from character animations. This is hardly noticable at first, but then you'll notice that some animations (like Spaz's sidekick) start disappearing in some areas. This, however, can get dangerous because of the way Jazz 2 handles animation overflows. If Jazz 2 runs out of animations completely, it crashes with an access violation. If you move into an area with new animations too quickly for the game to take away from the character animation, the game will crash. This means that certain attacks (Spaz's sidekick, and to a lesser extent Jazz's uppercut) that move the character into areas with more animations without first taking away from the older ones will cause the game to crash. In your case, however, it crashes when it starts. This is because the second the level starts, the game has to render so many animations, it instantly overflows (animations still go on even when they aren't onscreen) and the game crashes. Possible solutions include removing enemies, of course. Another option is to make them more similar. 5 enemies of the same type take less animation power than 5 of different types. Of course, 5 enemies of the same type will still take up more animation power than 1 enemy. Making the level bigger could help, but you'd also have to space out the enemies more, just as Newspaz said. The amount of enemies you need to have this problem is very high, and I dobut it would hurt the level way too much by removing some.

Good luck and sorry for the long post.